Expanding the Biocatalytic Scope of Enzyme-Loaded Polymeric Hydrogels

In recent years, polymeric hydrogels have appeared promising matrices for enzyme immobilization to design, signify and expand bio-catalysis engineering. Therefore, the development and deployment of polymeric supports in the form of hydrogels and other robust geometries are continuously growing to green the twenty-first-century bio-catalysis. Furthermore, adequately fabricated polymeric hydrogel materials offer numerous advantages that shield pristine enzymes from denaturation under harsh reaction environments. For instance, cross-linking modulation of hydrogels, distinct rheological behavior, tunable surface entities along with elasticity and mesh size, larger surface-volume area, and hydrogels’ mechanical cushioning attributes are of supreme interest makes them the ideal candidate for enzyme immobilization. Furthermore, suitable coordination of polymeric hydrogels with requisite enzyme fraction enables pronounced loading, elevated biocatalytic activity, and exceptional stability. Additionally, the unique catalytic harmony of enzyme-loaded polymeric hydrogels offers numerous applications, such as hydrogels as immobilization matrix, bio-catalysis, sensing, detection and monitoring, tissue engineering, wound healing, and drug delivery applications. In this review, we spotlight the applied perspective of enzyme-loaded polymeric hydrogels with recent and relevant examples. The work also signifies the combined use of multienzyme systems and the future directions that should be attempted in this field.

Fabrication and characterization of Cs2SnI6 perovskite films using SnI2 and I2 powders as reactants

In the recent years, cesium tin iodide (Cs2SnI6) double perovskite has emerged as a research hotspot in photovoltaics due to its exceptional stability and outstanding optoelectronic properties. In this work, we have utilized a reactant combination of SnI2 and I2 to prepare uniform Cs2SnI6 films via modified two-step process. The impact of the reaction conditions on the structural, morphological and optical properties is explored. It is found that optimizing the reaction conditions improves the phase stability and morphology of the films. The iodine-rich fabrication of the films ensued in enhanced PL and optical characteristics of the Cs2SnI6 with an optimal bandgap in the range of 1.21-1.34 eV. Additionally, we constructed all-inorganic photovoltaic devices FTO/TiO2/Cs2SnI6/Carbon utilizing optimized Cs2SnI6 films.

Learning from vernacular settlements. The role of traditional mitigation measures in Amalfi Coast

Vernacular settlements are mostly made up of buildings whose exceptional stability is testified by their survival over the centuries, even under natural and anthropogenic wounds. The unesco site of the Amalfi Coast shows a vast repertoire of cases to learn about the surviving examples of vernacular techniques and their structural qualities. It is possible to appreciate constructive protection measures that highlight the ancient actions to ensure the built environment's safety. This research aims to represent an effort in the knowledge of the traditional mitigation measures, often considered simply as local architectural elements, analyzing a large number of protective devices on the Amalfi Coast, to take the right actions in the future recovery, conservation, and maintenance operations.

Scaling up to meet new challenges of brain and behaviour: Deep brain electrophysiology in freely moving sheep

While rodents are arguably the easiest animals to use for studying brain function, relying on them as model species for translational research comes with its own sets of limitations. Here, we propose sheep as a practical large animal species for in vivo brain function studies performed in naturalistic settings. To demonstrate their experimental usefulness, we performed proof-of-principle deep brain electrophysiological recording experiments from unrestrained sheep. Recordings were made from cortex and hippocampus both whilst sheep performed goal-directed behaviours (two-choice discrimination tasks), and across states of vigilance that included natural sleep. Hippocampal and cortical oscillatory rhythms were consistent with those seen in rodents and non-human primates, and included cortical alpha oscillations during immobility, hippocampal theta oscillations (5-6Hz) during locomotion and hippocampal sharp wave ripple oscillations (~150 Hz) during immobility. Moreover, we found clear examples of neurons whose activity was modulated by task, speed of locomotion, spatial position, reward and vigilance states. Recordings were conducted over a period of many months. Due to the exceptional stability of individual electrodes we were able to record from some neurons continuously for more than 1 month. Together these experiments demonstrate that sheep are an excellent experimental animal model to use in longitudinal electrophysiological and imaging studies, particularly those requiring a large brained mammal, large scale recordings across distributed neuronal networks, experimentation outside the confounds of the traditional laboratory, or all the above concomitantly.

On-Surface Bottom-Up Construction of COF Nanoshells towards Photocatalytic H2 Production

The rational design of an outer shell is of great significance to promote the photocatalytic efficiency of core-shell structured photocatalysts. Herein, a covalent organic framework (COF) nanoshell was designed and deposited on the cadmium sulfide (CdS) core surface. A typical COF material, TPPA, featuring exceptional stability, was synthesized through interfacial polymerization using 1, 3, 5-triformylphloroglucinol (TP) and p-phenylenediamine (PA) as monomers. The nanoshell endows the CdS@TPPA nanosphere with ordered channels for unimpeded light-harvesting and fast diffusion of reactants/products and well-defined modular building blocks for spatially charge separation. Moreover, the heterojunction formed between CdS and TPPA can further facilitate the effective charge separation at the interface via lower exciton binding energy compared with that of pristine TPPA. By modulating the thickness of TPPA nanoshell, the CdS@TPPA nanosphere photocatalyst with the nanoshell thickness of about 8±1 nm exhibits the highest photocatalytic H2 evolution of 194.1 μmol h-1 (24.3 mmol g-1 h-1, 8 mg), which is superior to most of the reported COF-based photocatalysts. The framework nanoshell in this work may stimulate the thinking about how to design advanced shell architecture in the core-shell structured photocatalysts to achieve coordinated charge and molecule transport.

Exceptional stability of a perilipin on lipid droplets depends on its polar residues, suggesting multimeric assembly

Numerous proteins target lipid droplets (LDs) through amphipathic helices (AHs). It is generally assumed that AHs insert bulky hydrophobic residues in packing defects at the LD surface. However, this model does not explain the targeting of perilipins, the most abundant and specific amphipathic proteins of LDs, which are weakly hydrophobic. A striking example is Plin4, whose gigantic and repetitive AH lacks bulky hydrophobic residues. Using a range of complementary approaches, we show that Plin4 forms a remarkably immobile and stable protein layer at the surface of cellular or in vitro generated oil droplets, and decreases LD size. Plin4 AH stability on LDs is exquisitely sensitive to the nature and distribution of its polar residues. These results suggest that Plin4 forms stable arrangements of adjacent AHs via polar/electrostatic interactions, reminiscent of the organization of apolipoproteins in lipoprotein particles, thus pointing to a general mechanism of AH stabilization via lateral interactions.

Concept of Competitive Authoritarianism and Its Criticism in Scientific Literature

The concept of competitive authoritarianism by Steven Levitsky and Lucan Way has become one of the compelling responses to the decline of the transition paradigm that used to hold optimistic expectations about democratization of political regimes that combined elements of democracy and authoritarianism. According to Levitsky and Way’s logic, the presence of an authoritarian component does not allow one to characterize such mixed regimes as democratic, and in this sense, competitive authoritarianism is still authoritarianism. At the same time, it differs from other forms of authoritarian regimes due to the non-illusory ability of the opposition to compete for the executive power. The concept of competitive authoritarianism has been widely used in the study of political regimes, but the resulting important need for a deeper understanding of its assumptions has given rise to a number of critical evaluations among the researchers. The main criticism of the opponents regards the operationalization of the concept of “competitive authoritarianism”, the historical limitations of its usage, as well as Levitsky and Way’s idea that competitive authoritarian regimes are predetermined to democratize if they maintain broad and close ties with the West that are regarded as some kind of frozen objective reality. The article attempts to bring together the critical arguments that have been expressed in the research literature against the concept of competitive authoritarianism, and thereby contribute to a more balanced reception of this concept in the domestic scientific discourse. According to the author’s conclusion, the main flaws of the concept are related to the interpretation of the reasons for the vulnerability/stability of competitive authoritarian regimes. The focus on the role of the West and the regime’s ability to control the political process ignores a number of other significant factors, including the ability of the opposition to counter the current government with some real alternative, which is especially important in the Russian context, where the absence of such an alternative is one of the key reasons for the exceptional stability of the authoritarian regime.